Comparative study of human intestinal and hepatic esterases as related to enzymatic properties and hydrolizing activity for ester-type drugs.

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Abstract
To determine the exact role of intestinal esterase in the body, esterases were purified from human intestinal mucosa and liver and compared the enzymatic properties and substrate specificities with those of purified esterases. Esterase from human liver was purified 58-fold, by treatment with butanol, DE-52 and DEAE Sephadex A-50 column chromatographies, Sephadex G-200 gel filtration and isoelectric focusing. The purified preparation showed a single band by polyacrylamide gel electrophoresis. the MW of intestinal and hepatic esterases were determined to be 53,000-55,000 and 180,000, respectively, by gel filtration on Sephadex G-200. The activity of the purified intestinal and hepatic esterases was strongly inhibited by diethyl-p-nitrophenyl phosphate and DFP, and was not inhibited by eserine sulfate and p-chloromercuribenzoate. The purified esterases hydrolyzed ester-type drugs, i.e., aspirin, clofibrate, indanyl carbenicillin and procaine. Hepatic esterase had properties similar to those of intestinal esterase with respect to the sensitivity to organophosphate and the substrate specificity. The 2 purified esterases differed in properties i.e., MW, isoelectric point, thermostability and optimal pH.